I would like to ask for somebody to point me in the right direction - any literature I could read - regarding the mechanism behind color changes that an organic solution undergoes due to changes in pH. I am not referring to organic indicators or dyes, specifically. I have observed in my experiments that a certain polysaccharide solution is colorless at pH ≤ 6 and gradually turns yellowish-green as pH is increased to 11 at room temperature. I was wondering if there is an explanation for this phenomenon that relates to the compound's structure (i.e. presence of certain functional groups). Thanks!